Much of The Comedy of Errors is about mistaken identity, and the search for true identity. The most significant identity search belongs to S. Antipholus, who feels incomplete for any number of reasons. He seeks to fill the void about who he is by getting a family, a wife, or returning to a familiar place, but ultimately it seems he’s seeking to be defined by things outside of himself. This is particularly dangerous because of the issue of mistaken identity. Characters in the play are so positive about the identity of others that they ignore all the hints pointing to how they’re mistaken. Interestingly, this habit of being mistaken leads some of the characters to question their notions of their own identity.
How others identify each character is as important as how each character identifies himself. For instance, S. Antipholus’s and E. Antipholus’s self-perceptions are ultimately less important than the way other characters perceive them.